Web-supporting device

ABSTRACT

A supporting roller across which a flexible web moves is rotatably mounted at its midpoint on a longitudinal shaft and is pivotally movable with respect to said shaft. Three orthogonal axes pass through the midpoint. The first axis is the longitudinal aXis of the roller; the roller is adjustably positionable about the second axis; and the third axis is a gimbal axis about which the roller is free to rotate. In order to restrain the roller for these movements one end of the roller is provided with a roller bearing which is connected by flexures to an annulus extending around the shaft. In one embodiment the annulus is connected by a flexure arm to a lug which is longitudinally adjustable along a support post extending perpendicular from the shaft. Also, the post is adjustably positionable about the shaft so that the direction of the gimbal axis can be changed. In another embodiment a spring bracket biases the flexure member along its axis, the amount of the movement thereof being limited by a setscrew.

United States Patent John E. Morse; Richard A. Marsh, both of Rochester,N.Y. [21] Appl. No. 873,565

[72] Inventors {22] Filed Nov. 3, 1969 [45] Patented Sept. 28, 1971 [73]Assignee Eastman Kodak Company Rochester, N.Y.

[54] WEB-SUPPORTING DEVICE 11 Claims, 2 Drawing Figs.

52 U.S.Cl 226/21,

226/194 [51] 1m.c| ..B65h25/26 so FieldofSearch 226/180 PrimaryExaminer-Richard A. Schacher Att0rneysRobert W. Hampton and Gary D.Fields ABSTRACT: A supporting roller across which a flexible web movesis rotatably mounted at its midpoint on a longitudinal shaft and ispivotally movable with respect to said shaft. Three orthogonal axes passthrough the midpoint. The first axis is the longitudinal aXis of theroller; the roller is adjustably positionable about the second axis; andthe third axis is a gimbal axis about which the roller is free torotate. In order to restrain the roller for these movements one end ofthe roller is provided with a roller bearing which is connected byflexures to an annulus extending around the shaft. in one embodiment theannulus is connected by a flexure arm to a lug which is longitudinallyadjustable along a support post extending perpendicular from the shaft.Also, the post is adjustably positionable about the shaft so that thedirection of the gimbal axis can be changed. In another embodiment aspring bracket biases the flexure member along its axis, the amount ofthe movement thereof being limited by a setscrew.

PATENTED SEP28 l9?! JOHN E. MORSE RICHARD A, MARSH INVENTORS ATTORNEYSBACKGROUND-OF THE INVENTION 1. Field of the Invention This inventionrelates to a web-supporting device and more particularly to anadjustably positioned roller which is pivotal about a gimbal axispassing through the midpoint of the roller.

2. Description of the Prior Art Various attempts have been made in theprior art to provide guides and suitable constraints for flexible beltsor webs which are fed from a supply roll to a takeup roll. Also, similardevices have been provided for endless belts. Idler rollers have beenprovided which are selfaligned by a belt or Web which tends to run offone side of the roller. To provide even tension across the belt, rollershave been mounted for pivotal movement about a center point, asdisclosed in commonly assigned US. Pat. No. 3,161,283 to Knab et al.which issued Dec. 15, I964; U.S. Pat. No. 3,315,859 to Owen et al. whichissued Apr. 25, 1967; and [1.8. Pat No; 3,342,389 which issued toDrexler on Sept. 19, 1967. In each of these devices means are providedat the edge of the roller for sensing misalignment of the belt causingthe roller to pivot in such a way as to correct this misalignment. Sucharrangement can result in damage to the edge of the web and in anunstable system whereby the web is continually wandering back and forthacross the roller. In a web path, where a web is subject to bothupstream and downstream constraints, it is desired that the rollerprovide a stable adjustable lateral position of the Web without imposingnonunifonn stresses on the web.

SUMMARY OF THE INVENTION In the present invention a flangeless supportroller for a web is mounted for rotational and pivotal movement about amidpoint, but the roller is further restrained for movement about onlyone of three orthogonal axes passing through the roller. One of theseaxes is the longitudinal axis of the roller. The second orthogonal axisis the axis about which the roller is to be adjusted, and the thirdorthogonal axis is the axis about which the roller is free to rotate.This latter axis will be referred to as the gimbal axis. Thus, byproviding means for adjusting the direction of the longitudinal rolleraxis with respect to the web about the second axis and for allowing thelongitudinal roller axis to be free about the third or gimbal axis, atracking roller is provided which allows adjustment of the lateral webposition at the roller and imposes the proper restraints on the webwithout imposing additional unwanted restraints.

This is accomplished in the present invention by providing means at oneend of the roller for adjustably positioning a Iongitudinal axis of theroller about the second orthogonal axis and for positioning thedirection of the second and third orthogonal axes with respect to theweb. In one embodiment this adjustment means includes an annulussurrounding a longitudinal shaft which is nominally parallel to anapproach and an exit plane of the web and is connected to a rollerbearing at one end of the roller for adjustably positioning the roller.The annulus in turn is connected to a flexure arm extendingsubstantially perpendicularly from the longitudinal axis. A support postextends perpendidularly from the longitudinal shaft andis provided withmeans connected to the flexure arm for adjustably positioning the latterwith respect to the longitudinal shaft. In addition, the post isadjustably mounted for pivotal adjustment about the longitudinal shaftto adjustably position the direction in which the second and thirdorthogonal axes lie with respect to the web. Conveniently, a counterbalance is provided at the opposite end of the roller to counter balancethe weight of the bearing, annulus and flexure arm at the opposite end.I

In an alternative embodiment, the flexure arm is connected to a biasingbracket which exerts a longitudinal force on the flexure member and hasa 'se'tscrew which limits the amount of movement that can be imposedupon the flexure member and hence on the end of the roller.

There are. at least two uses for rollers constructed in accordance withthis invention: If the gimbal axis is substantially parallel to thedirection of the web approach plane, the roller can be used with a webwhich is laterally constrained upstream and angularly constraineddownstream or it can be used with a web which is laterally constrainedupstream and laterally constrained downstream. When so used, the rollermaintains a stable adjustable lateral position for the web at the rollerlocation and does not cause uneven tension distribution in the enteringor leaving web sections.

Additional advantages of this invention will become apparent from thedescription which follows, taken in conjunction with the accompanyingdrawings.

BRIEF DESCRIPTION OF THE DRAWINGS FIG. 1 is a perspective view of oneform of the present invention, with parts broken away, for clarity ofillustration; and

FIG. 2 is a fragmentary perspective view of an alternative gimbal axisadjustment.

DESCRIPTION OF THE PREFERRED EMBODIMENT In accordance withthisinvention, a roller assembly R includes a roller 2, as shown is mountedfor rotation and pivotal movement in a bearing member 3 having ballbearings 4 mounted between an inner race 6 and slightly loose outer race8 at the midpoint 10 of the roller. Inner race 6 is fixedly connected toa shaft 12, having an axis 13 and extending from a frame or base 14 ofthe apparatus in which the tracking roller is used.

Roller 2 is adapted to support a web 16, which may move in the directionof arrow I8 and engages roller 2 along an approach plane and departstherefrom along an exit plane as shown. Roller support shaft 12 isnominally mounted so as to be generally parallel with both the approachand exit plane of web 16. However, in actual practice it is virtuallyimpossible to provide such a precise alignment of shaft 12. Therefore,to compensate for any misalignment, means must be provided for adjustingthe position of roller 2 with respect to shaft 12 so that it causes theweb to seek the desired lateral position without imposing any unwantedconstraints on web 16 as it passes thereacross.

To accomplish this, bearing assembly 20 is provided which includes ballbearings 22 between an inner race 23 and an outer race 24; fixedlyconnected to the roller. Conveniently, outer race 24 'is fixedly mountedin the end of the roller and the inner race 23 is free to rotatetherein. A roller adjustment assembly-A is provided which in thisembodiment includes an annulus 26 extending around shaft 12 adjacentbearing assembly 20 and is connected to inner race 23, as by a pair offlexure members at opposite sides thereof, such as flexure member 28.

Three orthogonal axes pass through midpoint 10 about which movement orposition of roller 2 is important. These axes are roller axis 30,adjustment axis 32, and gimbal axis 34. Through roller adjustmentassembly A, the roller is constrained so that it is free to rotate aboutgimbal axis 34, as illustrated by arrows 35, but is adjustablypositionable with respect to adjustment axis 32. To provide thisadjustment, an adjustment post 36 extends perpendicularly from shaft 12and is attached thereto by a clamp 38. A flexure arm 40 extends fromannulus 26 and has a reduced portion 42 which serves as a pivot by whichflexure arm 40 is attached to a lug 44. Lug 44 is adjustable along post36 by means of spaced adjustment nuts 46. By this means the end ofroller 2 is moved in the direction of arrows 48 to adjustably positionthe roller about axis 32. The direction of gimbal axis 34 can beadjusted with respect to the approach and exit planes of the web bymeans of clamp 38 which may be loosened to rotate post 36 about shaft 12in the direction of arrows 50. The weight of bearing assembly 20,annulus 26 and flexure arm. 40 is counterbalanced conveniently bythickened portion 51 at the opposite end of roller 2.

It will be noted that reduced section 42 of flexure 40 serves as a pivotpoint to permit rotation of roller about gimbal axis 34 withoutinterference from the roller adjustment assembly A. Also, flexures 28permit pivotal movement of roller 2 about adjustable axis 32 asadjustment lug 44 is moved through its adjustment range. However, afteradjustment, the position of roller 2 about axis 32 is fixed.

An alternative adjustment assembly A is shown in FIG. 2 wherein thereduced end 42 of flexure 40 is attached to a U- shaped spring bracket52 which in turn is attached to frame or housing 14 as shown. Springbracket 52 exerts a force on flexure 40 in the direction of arrow 54.The extent of movement of flexure 40 is limited by an adjustablesetscrew 56.

From the foregoing, the advantages of this invention are readilyapparent. A web-handling device is provided which facilitates freemovement of the roller about a gimbal axis extending through themidpoint of the roller, but the roller is adjustably fixed about anadjustment axis which is perpendicular to the gimbal axis and to thelongitudinal axis of the roller. Thus, the longitudinal axis of theroller can be positioned so as to be exactly perpendicular to thedesired web approach direction and the direction of the gimbal axis maybe adjusted to be substantially parallel with the web approach plane asdesired for the particular use for which theroller is to be putdepending on the upstream and downstream constraints already exerted onthe web.

The invention has been described in considerable detail with referenceto preferred embodiments thereof, but it will be understood thatvariations and modifications can be effected within the spirit and scopeof the invention.

We claim:

1. A web-tracking device for transporting a web between upstream anddownstream constraints and having first, second and third orthogonalaxes, said web being adapted to come into engagement with said trackingdevice along an upstream approach direction, said device comprising:

means defining a fixed longitudinal axis;

a roller for supporting a web, said roller having two ends and amidpoint and being rotatably supported solely at said midpoint forrotation about said fixed axis said orthogonal axes extending throughsaid midpoint, wherein said first orthogonal axis is said roller axisand is normally coincident with said fixed axis; and

means for constraining said roller for free pivotal movement about saidthird orthogonal axis as a gimbal axis and for adjustment of said rolleraxis about said second orthogonal axis so that said roller axis issubstantially pcrpcndicular to said approach direction.

2. A web-tracking device as claimed in claim 1 wherein said constrainingmeans includes:

means connected to one end of said roller adjustably movable in adirection perpendicular to said fixed axis to adjustably position saidroller about said second orthogonal axis.

3. A web-tracking device for transporting a web between upstream anddownstream constraints and having first, second and third orthogonalaxes, said web being adapted to come into engagement with said handlingdevice along an upstream approach direction, said device comprising:

a fixed shaft having alongitudinal axis;

a roller for supporting a web, said roller having first and second endsand a midpoint through which said orthogonal axes extend, said firstorthogonal axis being said roller axis;

mounting means concentrically arranged with respect to said midpoint asthe sole means for rotatably mounting said roller on said shaft so thatsaid roller'axis if free to pivot in all directions about said'midpoint,being unsupported at said first and second ends;

first adjustable positioning means for adjustably fixing the position ofsaid roller axis about said second orthogonal axis so that said rolleraxis is substantially perpendicular to said upstream approach'directionwithout restraining movement of said roller aboutsaid third orthogonalaxis. 4. A web-tracking device as claimed in claim 3, further including:

second adjustable positioning means for adjustably positioning saidorthogonal axes about said longitudinal axis. 5. A web-tracking deviceas claimed in claim 3, wherein said first adjustable positioning meansincludes:

a bearing rotatably attached to said first end of said roller; meansconnected to said bearing for adjustably locating said one end of saidroller transversely with respect to said shaft. 6. A web-tracking deviceas claimed in claim 5, further including:

counterbalance means on said second end of said roller to counterbalancesaid bearing. 7. Aweb-tracking device as claimed in claim 5, whereinsaid adjustable locating means includes:

an annulus extending around said shaft and connected to said bearing; anarm, having a longitudinal axis, extending from said annulus; meansbiasing said arm along said longitudinal axis thereof;

and means limiting the movement of said arm' in response to said biasingmeans. 8. A web-tracking device as claimed in claim 5, wherein saidlocating means includes:

an annulus extending around said shaft and connected to said bearing: asupport post spaced from said annulus and extending perpendicularly fromsaid shaft; an arm extending from said annulus; I adjustment means onsaid post connected to said arm for positioning said one end of saidroller with respect to said shaft. 9. A web-tracking device as claimedin claim 8, further including:

adjustable clamp means for adjustably connecting said post about saidshaft. 10. A web-tracking device as claimed in claim 8, furtherincluding: v

first means pivotally connecting said annulus to said bearing; andsecond means pivotally connecting said arm to said adjustment means. 11.A web-tracking device as claimed inclaim 10 wherein said first andsecond means are flexure members.

1. A web-tracking device for transporting a web between upstream anddownstream constraints and having first, second and third orthogonalaxes, said web being adapted to come into engagement with said trackingdevice along an upstream approach direction, said device comprising:means defining a fixed longitudinal axis; a roller for supporting a web,said roller having two ends and a midpoint and being rotatably supportedsolely at said midpoint for rotation about said fixed axis, saidorthogonal axes extending through said midpoint, wherein said firstorthogonal axis is said roller axis and is normally coincident with saidfixed axis; and means for constraining said roller for free pivotalmovement about said third orthogonal axis as a gimbal axis and foradjustment of said roller axis about said second orthogonal axis so thatsaid roller axis is substantially perpendicular to said approachdirection.
 2. A web-tracking device as claimed in claim 1 wherein saidconstraining means includes: means connected to one end of said rolleradjustably movable in a direction perpendicular to said fixed axis toadjustably position said roller about said second orthogonal axis.
 3. Aweb-tracking device for transporting a web between upstream anddownstream constraints and having first, second and third orthogonalaxes, said web being adapted to come into engagement with said handlingdevice along an upstream approach direction, said device comprising: afixed shaft having a longitudinal axis; a roller for supporting a web,said roller having first and second ends and a midpoint through whichsaid orthogonal axes extend, said first orthogonal axis being saidroller axis; mounting means concentrically arranged with respect to saidmidpoint as the sole means for rotatably mounting said roller on saidshaft so that said roller axis is free to pivot in all directions aboutsaid midpoint, being unsupported at said first and second ends; firstadjustable positioning means for adjustably fixing the position of saidroller axis about said second orthogonal axis so that said roller axisis substantially perpendicular to said upstream approach directionwithout restraining movement of said roller about said third orthogonalaxis.
 4. A web-tracking device as claimed in claim 3, further including:second adjustable positioning means for adjustably positioning saidorthogonal axes about said longitudinal axis.
 5. A web-tracking deviceas claimed in claim 3, wherein said first adjustable positioning meansincludes: a bearing rotatably attached to said first end of said roller;means connected to said bearing for adjustably locating said one end ofsaid roller transversely with respect to said shaft.
 6. A web-trackingdevice as claimed in claim 5, further including: counterbalance means onsaid second end of said roller to counterbalance said bearing.
 7. Aweb-tracking device as claimed in claim 5, wherein said adjustablelocating means includes: an annulus extending around said shaft andconnected to said bearing; an arm, having a longitudinal axis, extendingfrom said annulus; means biasing said arm along said longitudinal axisthereof; and means limiting the movement of said arm in response to saidbiasing means.
 8. A web-tracking device as claimed in claim 5, whereinsaid locating means includes: an annulus extending around said shaft andconnected to said bearing: a support post spaced from said annulus andextending perpendicularly from said shaft; an arm extending from saidannulus; adjustment means on said post connected to said arm forpositioning said one end of said roller with respect to said shaft.
 9. Aweb-tracking device as claimed in claim 8, further including: adjustableclamp means for adjustably connecting said post about said shaft.
 10. Aweb-tracking device as claimed in claim 8, further including: firstmeans pivotally connecting said annulus to said bearing; and secondmeans pivotally connecting said arm to said adjustment means.
 11. Aweb-tracking device as claimed in claim 10 wherein said first and secondmeans are flexure members.